I think we all knew this, but in this review of Yves Gingras's Bibliometrics and Research Evaluation: Uses and Abuses we read of a detailed examination of the topic. "While study of publication and citation patterns, “on the proper scale, provides a unique tool for analyzing global dynamics of science over time,” the book says, the 'entrenchment' of increasingly (and often ill-defined) quantitative indicators in the formal evaluation of institutions and researchers gives way to their abuses."